Method and kit for retrofitting elevator machines with thrust bearing, and retrofitted elevator machine

ABSTRACT

Disclosed is a method for retrofitting an elevator machine with a thrust bearing, including removing, from a bearing stand, a first cover plate, providing access to an end portion of a motor shaft, securing an extension shaft against the end portion of the motor shaft, securing a thrust bearing housing against or axially offset from the bearing stand, positioning a thrust bearing in the bearing housing, wherein an inner race of the thrust bearing is securely positioned against, and axially fixed to, the extension shaft, and an outer race of the thrust bearing is securely positioned against the bearing housing, and securing a second cover plate to the bearing housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Division of U.S. application Ser. No. 15/359,238filed Nov. 22, 2016, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND

Elevator systems are useful for carrying passengers between variouslevels in a building. There are various types of elevator systems. Someare referred to as traction-based systems because of reliance upontraction between a drive sheave and hoisting ropes to move and positionthe elevator car. Elevator machines in traction-based systems include amotor, drive sheave and a brake. There are a variety of known brakeconfigurations.

Some elevator codes require braking functions that are not provided byolder machines. Supplemental brakes can be added to meet such coderequirements. One type of supplemental brake is referred to as a ropegrabber because it provides a mechanism for clamping onto the ropingarrangement. A rope grabber prevents the roping arrangement from moving,which maintains a position of an elevator car within a hoistway.

Rope grabber braking has drawbacks. One drawback is that the ropegrabber system needs to be positioned below the elevator machine. Thisrequires taking up space within the hoistway or raising the elevatormachine within a machine room for providing adequate spacing for therope grabber system. Raising elevator machines is very costly, requiresadequate clearance in the machine room, and may require new ropes. Suchinstallation is cramped, resulting in limited accessibility for futureservice. Additionally, some elevator applications exceed the capabilityof existing available rope grabbing devices, or have other spacelimitations. Rope grabbers, by applying braking forces directly onto theropes, increase rope wear.

Other options to meet contemporary regulatory braking requirementsinclude replacing the existing elevator machine with a completely newmachine that includes necessary braking capabilities. Such action,however, can be costly and time consuming, and results in wastingotherwise serviceable elevator machinery.

The rotating portion of an elevator machine includes a main shaftassembly supported on bearings. The main shaft bearings are supported instands or housings on the stationary structure of the machine. The mainshaft bearings are arranged to support large radial loads developed bythe weight of the motor shaft assembly, the weight of the elevator car22 (FIGS. 1 and 2) and other loads transmitted to the elevator drivesheave by the roping arrangement 26.

The main shaft bearings may be implemented as sleeve bearings, alsoknown as journal bearings. The main shaft bearings may alternatively beimplemented as rolling element bearings, also known as anti-frictionbearings.

On some elevator machines, the main shaft bearings allow some amount ofaxial movement of the main shaft during rotation and operation of theelevator machine. Axial movement of the main shaft may occur in mainshaft designs utilizing sleeve bearings and also designs utilizingrolling bearing elements.

When applying certain componentry to the main shaft, for properoperation of the componentry the axial movement of the main shaft mustbe held at or near to zero. Disc brake componentry, e.g., tolerates zeroor near zero axial movement of the main shaft for proper operation.

Innovations have sought to enhance braking of installed elevators byreplacing contemporary braking componentry with disc brake componentry.In view of tight tolerances associated with disc brakes, the pendingdisclosure provides a system that limits axial motion for the main shaftdisposed between shaft bearing stands.

BRIEF DESCRIPTION

Disclosed is a method for retrofitting an elevator machine with a thrustbearing, comprising removing, from a bearing stand, a first cover plate,providing access to an end portion of a motor shaft, securing anextension shaft against the end portion of the motor shaft, securing athrust bearing housing against, or axially offset from, the bearingstand, positioning the thrust bearing in the bearing housing, wherein:an inner race of the thrust bearing is securely positioned against, andaxially fixed to, the extension shaft, and an outer race of the thrustbearing is securely positioned against the bearing housing, and securinga second cover plate to the bearing housing.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the extension shaftincludes a first base plate that is secured to the end portion of themotor shaft, and the thrust bearing housing includes a second base platethat is secured against or axially offset from the bearing stand.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the end portion of themotor shaft and bearing stand are provided with threaded bores tosecurely position the first and second base plates.

In addition to one or more of the features described above, or as analternative, further embodiments may include that an outward extendingportion of the first base plate includes a shoulder that is a firstbearing seat for limiting axial motion of the thrust bearing inner race,and an inward extending portion of the second base plate is a secondbearing seat for limiting axial motion of the thrust bearing outer race.

In addition to one or more of the features described above, or as analternative, further embodiments may include that a retaining nutsecured to an end portion of the extension shaft is a third bearing seatfor limiting axial motion of the thrust bearing inner race, and thesecond cover plate has an annular boss, which is a fourth bearing seatfor limiting axial motion of the thrust bearing outer race.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the second coverplate, which includes the annular boss, are is axially spaced from theend portion of the extension shaft.

Further disclosed is a kit for retrofitting an elevator machine with athrust bearing, wherein: from a bearing stand of the elevator machine, afirst cover plate is capable of being removed, providing access to anend portion of a motor shaft, and the kit comprises: an extension shaft,capable of being secured against the end portion of the motor shaft, athrust bearing housing, capable of being secured against, or axiallyoffset from, the bearing stand, the thrust bearing, capable of beingpositioned in the thrust bearing housing, wherein: an inner race of thethrust bearing is securely positioned against, and axially fixed to, theextension shaft, and an outer race of the thrust bearing is securelypositioned against the thrust bearing housing, and a second cover plate,capable of being secured to the bearing housing.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the extension shaftincludes a first base plate, capable of being secured to the end portionof the motor shaft, and the thrust bearing housing includes a secondbase plate, capable of being secured to, or axially offset from, thebearing stand.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the end portion of themotor shaft and bearing stand are capable of being provided withthreaded bores and the kit further includes a first bolt to securelyconnect the first base plate thereto and, either (i) a second bolt, or(ii) an extension rod, to securely connect the second base platethereto.

In addition to one or more of the features described above, or as analternative, further embodiments may include that an outward extendingportion of the first base plate includes a shoulder that is a firstbearing seat capable of limiting axial motion of the thrust bearinginner race, and an inward extending portion of the second base plate isa second bearing seat capable of limiting axial motion of the thrustbearing outer race.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the kit includes aretaining nut, securable to an end portion of the extension shaft, whichis a third bearing seat capable of limiting axial motion of the thrustbearing inner race, and the second cover plate has an annular boss,which is a fourth bearing seat capable of limiting axial motion of thethrust bearing outer race.

In addition to one or more of the features described above, or as analternative, further embodiments may include that the second coverplate, including the annular boss, when installed in an elevatormachine, are axially spaced from the end portion of the extension shaft.

In addition to one or more of the features described above, or as analternative, further embodiments may include extension rods and a thirdcover plate, with a first oil seal secured thereto, capable of beingsecured against the bearing stand, and wherein, the thrust bearinghousing includes a second oil seal secured thereto and the thrustbearing housing is capable of being axially offset from the bearingstand with the extension rods.

Additionally disclosed is an elevator machine retrofitted with a thrustbearing, wherein: the machine includes a bearing stand, from which afirst cover plate has been removed, providing access to an end portionof a motor shaft, the elevator machine comprising: an extension shaftsecured against the end portion of the motor shaft, a thrust bearinghousing secured against, or axially offset from, the bearing stand, thethrust bearing positioned in the bearing housing, wherein: an inner raceof the thrust bearing is securely positioned against, and axially fixedto, the extension shaft, and an outer race of the thrust bearing issecurely positioned against the bearing housing, and a second coverplate secured to the bearing housing.

In addition to one or more of the features described above, or as analternative, further embodiments may include a third cover plate, with afirst oil seal secured thereto, secured against the bearing stand, andwherein, the thrust bearing housing includes a second oil seal securedthereto, and the thrust bearing housing is axially offset from thebearing stand with extension rods.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 illustrates an exemplary elevator system;

FIG. 2 illustrates an exemplary elevator machine;

FIG. 3 illustrates another exemplary elevator machine;

FIG. 4 illustrates another view of the elevator machine of FIG. 3,wherein components of the elevator machine unaffected by the disclosedembodiments are removed for visual clarity;

FIG. 5 illustrates a kit according to a disclosed embodiment;

FIG. 6 illustrates the elevator machine of FIG. 3, partially modifiedaccording to a disclosed embodiment to receive the kit of FIG. 5;

FIG. 7 illustrates the elevator machine of FIG. 4, further modified byutilizing components of the kit of FIG. 5, according to a disclosedembodiment; and

FIG. 8 illustrates the elevator machine of FIG. 4, modified according toan alternative embodiment, by utilizing various alternative componentsof the kit of FIG. 5.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

FIG. 1 schematically shows selected portions of an exemplary elevatorsystem 20. An elevator car 22 is situated for movement within a shaft orhoistway 24. The elevator car 22 is supported by a roping arrangement26.

An elevator machine 30, illustrated in greater detail in FIGS. 2-3,causes desired movement of the elevator car 22 to provide elevatorservice. The elevator machine 30, which could be a traction elevatormachine, is supported on a machine frame, or bed plate 36 within amachine room 38. The elevator machine 30 includes a shaft 40, a drivesheave 42 on a sheave flange 43 (FIG. 3), and the sheave 42 drives theropes 26 (FIG. 2). Integral with the drive sheave 42 is a brake drum 44.A brake arm assembly 46, with brake shoe (not illustrated), and brakearms 32 applies braking forces to the brake drum 44. A brake magnethousing 48 is provided as a part of the brake system, operativelyconnected to the brake arms 32.

As illustrated in FIG. 3, the elevator machine 30 includes a motor fieldframe 50 housing a motor rotating element 51, a front bearing stand 52,with a front bearing cover 54. On the rear of the elevator machine 30,there is a rear bearing stand 56 with a first rear bearing cover plate58.

Within the front and rear bearing stands 52, 56, as illustrated in FIG.4, is a front portion 60 of the motor shaft 40 and a rear portion 62 ofthe motor shaft 40. Rotationally supporting the respective front andrear portions 60, 62 of the motor shaft 40 is a front motor shaftbearing journal 64 and a rear motor shaft bearing journal 66. Thebearing journals 64, 66 are positionally supported by a front sleevebearing 68 and a rear sleeve bearing 70.

Turning to FIGS. 5-7, illustrated are components, which can be providedin a kit, and a method for retrofitting the elevator machine 30 with athrust bearing 71. In view of tight tolerances associated with certaincomponentry, including for example disc brakes, the disclosed methodprovides a system that limits front to back motion of the elevatormachinery disposed between the bearing stands 52, 56.

The method includes removing, from the rear bearing stand 56, the rearcover plate 58 (FIG. 6) connected by bolts 90, providing access to therear portion 62 of the motor shaft 40. The method includes securing anextension shaft 72 (FIGS. 5, 7) against the rear portion 62 of the motorshaft 40 (FIG. 7), and securing a thrust bearing housing 73 against therear bearing stand 56 (FIG. 7). The method further includes positioningthe thrust bearing 71 in the thrust bearing housing 73.

According to a disclosed embodiment, an inner race 75 (FIGS. 5, 7) ofthe thrust bearing 71 fits against the extension shaft 72. An outer race77 of the thrust bearing 71 fits against the inside of the radiallyouter structure of the thrust bearing housing 73.

The method also includes securing a second rear outer cover plate 79(FIG. 7) to the rear portion 80 of the thrust bearing housing 73.

As illustrated in FIG. 5, the extension shaft 72 includes a first frontbase plate 81, secured to the rear portion 62 of the motor shaft 40. Thethrust bearing housing 73 includes a second front base plate 83, securedto the rear portion of the bearing stand 56.

The rear portion 62 of the motor shaft and the rear portion 84 of thebearing stand 56 are provided with threaded bores 85, 87 to apply afirst bolt 89 (FIGS. 5, 7) and a second bolt 91. Alternatively, bolts 90can be reused in the holes already the bearing stand 56 (FIG. 6). Thebolts 89, 91 securely position the first base plate 81 of the extensionshaft 72 and second base plate 83 of the thrust bearing housing 73. Inone embodiment, the first bolt 89 and the second bolt 91 are each setsof bolts, such as three bolts per set, to provide the securedconnection.

A shaft shoulder 92 on an outward extending portion 93 (FIG. 5) of thefirst base plate 81, having a larger diameter than the extension shaft72, is a first bearing front seat for limiting axial forward motion ofthe thrust bearing inner race 75. The shoulder 92 has an axial lengththat enables the inner race 75 to flush mount with the front of theouter race 77. On the other hand, an inward extending portion 95 of thesecond base plate 83 is a second bearing front seat for limiting axialforward motion of the thrust bearing outer race 77.

A retaining nut 97 secured to a rear portion 99 of the extension shaft72 is a first bearing rear seat for limiting rearward motion of thethrust bearing inner race 75. The second outer cover plate 79 has aforward extending annular boss 101, which is a second bearing rear seatfor limiting rearward motion of the thrust bearing outer race 77.

As illustrated in FIG. 7, the second outer cover plate 79, including theannular boss 101 (FIG. 5), are spaced from the threaded rear portion 99of the extension shaft 72 and retaining nut 97. This configurationprovides buffer spacing as may be needed due to allowable forward andrearward motion of the elevator machine 30.

An alternative embodiment is illustrated by additional kit components inFIG. 5 and the installed components in FIG. 8. As compared with theembodiment in FIG. 7, the embodiment in FIG. 8 illustrates the thrustbearing housing 73 mounted rearwardly offset from the rear bearing stand56. The offset is provided via threaded extension rods 111 in place ofscrews 91 (FIG. 7), a relatively longer extension shaft 113, and oilseals 115, 117 added to retain lubricant in the bearing stand 56 and thethrust bearing housing 73.

A rear bearing cover plate 119, which is a third outer cover plate, hasa center hole 121 for the extension shaft 113 to pass through. FIG. 5illustrates a rear surface 118 of the bearing cover plate 119 with oilseal 115 mounted thereto. FIG. 8 illustrates the thrust bearing housing73 with oil seal 117 mounted to a front surface 120 (FIG. 5) of the baseplate 83. The extension shaft 113 is long enough to provide an axial gapbetween the oil seals 115, 117, providing spacing for adjusting the tiltand alignment of the thrust bearing housing 73 as required.

As illustrated in FIG. 8, axially stabilizing rear bearing cover plate119 and the base plate 83 (FIG. 5) of the thrust bearing housing 73, aresecuring members 122, 123, 125. The securing members 122, 123, 125 aredisposed on the front facing 131 surface of the bearing cover plate 119and on front 120 and rear 133 facing surfaces of the base plate 83 (FIG.5). As illustrated in FIG. 5, these securing members are threaded nuts.For axial stabilization of the bearing inner race 75, a shoulder 127 onthe extension shaft 113 is provided, which is long enough to serve thesame purpose of the shoulder 92 in the embodiment of FIG. 5.

Further within the scope of the disclosed embodiments is a standalonekit containing the components for retrofitting the thrust bearing 71 tothe elevator machine 30, and an elevator machine 30 retrofitted toinclude a thrust bearing 71. Such embodiments would have the samecomponents as identified in the method for installing the thrust bearing71 and would provide the same benefits, i.e., a system that limits axialmotion of the elevator machinery disposed between the bearing stands 52,56.

As referenced above and illustrated in FIG. 3, the terms “front”,“forward”, “rear” and “rearward”, with and without “end” or “portion”,which are implicit where reasonable, are relative to the longitudinalaxis 33A for the elevator machine. The terms “inner”, “inward”, “outer”and “outward”, also with and without “end” or “portion”, which areimplicit where reasonable, are relative to the radial axis 33R for theelevator machine.

It is to be appreciated that “front” and “rear”, with respect to, e.g.,the installation of the thrust bearing kit, are reversible orientations,depending on installation needs. Those skilled in the art having thebenefit of this description will realize that a variety of thrustbearing 71 configurations could be used that are different than theillustrated example. The techniques associated with the exampleretrofitting procedure may be used in a variety of elevator systemconfigurations to retrofit a previously installed elevator machine 30with a thrust bearing 71.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthe essence of this invention. The scope of legal protection given tothis invention can only be determined by studying the following claims.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,element components, and/or groups thereof.

While the present disclosure has been described with reference to anexemplary embodiment or embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe present disclosure. In addition, many modifications may be made toadapt a particular situation or material to the teachings of the presentdisclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this present disclosure, but that the present disclosurewill include all embodiments falling within the scope of the claims.

What is claimed is:
 1. A method for retrofitting an elevator machinewith a thrust bearing, wherein the elevator machine includes a bearingstand, a sleeve bearing supported in the bearing stand, a motor shaftsupported by the sleeve bearing, and an end portion of the motor shaftbeing accessible through the sleeve hearing, the method comprising:removing, from the bearing stand, a first cover plate, providing accessto the end portion of the motor shaft; securing an extension shaftaxially against the end portion of the motor shaft, the extension shaftextending in an axial rearward direction from the motor shaft; securinga base plate against, or axially offset from, an axial end of thebearing stand, wherein a thrust bearing housing is disposed axiallyagainst and extends axially rearward from the base plate, and whereinthe extension shaft extends axially through the base plate and thethrust bearing housing; positioning the thrust bearing in the thrustbearing housing, wherein: an inner race of the thrust bearing issecurely positioned radially against, and axially fixed to, theextension shaft; and an outer race of the thrust bearing is securelypositioned radially against the thrust bearing housing; securing aretaining nut to an end portion of the extension shaft, limiting axialrearward motion of the thrust bearing inner race; and securing a secondcover plate against an axial end of the thrust bearing housing, axiallyrearward spaced apart from the thrust bearing, the extension shaft andthe retaining nut.
 2. The method of claim 1, wherein: the extensionshaft includes another base plate that is secured to the end portion ofthe motor shaft; and the thrust bearing housing includes the base platethat is secured against or axially offset from the bearing stand.
 3. Themethod of claim 2, wherein the end portion of the motor shaft andbearing stand are provided with threaded bores to securely position thebase plates.
 4. The method of claim 3, wherein: an outward extendingportion of the other base plate includes a shoulder that is a firstbearing seat for limiting axial motion of the thrust bearing inner race;and an inward extending portion of the base plate is a second bearingseat for limiting axial motion of the thrust bearing outer race.
 5. Themethod of claim 4, wherein: the retaining nut secured to the end portionof the extension shaft is a third bearing seat for limiting axial motionof the thrust bearing inner race; and the second cover plate has anannular boss, which is a fourth bearing seat for limiting axial motionof the thrust bearing outer race.
 6. The method of claim 5, wherein thesecond cover plate, which includes the annular boss, is axially spacedfrom the end portion of the extension shaft.